Johnson, 22, was originally signed by the Patriots as a rookie free agent on May 19, 2014, out of Maine. He was released by the Patriots on June 9, 2014. The 5-foot-11, 190-pounder tied for the team lead with 60 receptions for 608 yards and two touchdowns in 2013. Johnson finished his college career with 116 receptions for 1,165 yards and four touchdowns.

McDonald, 23, had a career-best 51 receptions for 956 yards as a senior in 2013 at South Carolina State. The 6-3, 190-pounder finished his college career with 159 receptions for 2,389 receiving yards.